Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 2X2 block with tail 1,1 1,2 1,3 2,2 2,3 in any orientation.
A146051
Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 2X2 block with tail 1,1 1,2 1,3 2,2 2,3 in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =3a(9) =3a(10) =13a(11) =13a(12) =35a(13) =35a(14) =181a(15) =181a(16) =1303a(17) =1303a(18) =13131a(19) =13131a(20) =161693a(21) =161693a(22) =2592581a(23) =2592581a(24) =57377381a(25) =57377381a(26) =1720164275a(27) =1720164275
External references
- oeis: A146051